This invention relates to a craft interface device for executing maintenance and provisioning operations in a telecommunications system. This also invention relates to an associated method.
A Litespan.TM. -type telecommunications system is a group of one or more Litespan.TM. terminals connected together, for example, in a chain configuration by optical fiber. Each Litespan.TM. terminal comprises a rack or other enclosure with multiple banks each having a printed circuit board "backplane." These printed circuit boards each have a plurality, e.g., sixty-five, of numerically ordered slots in which various cards, such as fiber cards and subscriber line cards, are vertically disposed.
Each Litespan.TM. terminal includes a common control (CC) bank and a number of subscriber banks (fiber banks, channel bahks) for various kinds of fiber connections and various kinds of subscriber drops such as POTS, ISDN, HFC, etc. A fiber bank includes one backplane, power supplies, plug-in bank control units and fiber cards. A channel bank includes a single backplane, power supplies, plug-in bank control units and subscriber line cards. Each remote terminal (RT) access multiplexer communicates on one or both sides with a fiber span and may also include various types of subscriber drops. A local telephone company can begin operations with rack shelves only partially filled with backplanes and with the backplane slots only partially occupied and fill in the remaining backplanes and slots as the number of subscribers and service requirements increase.
In a Central Office (CO) of a telephone company, one terninal, called the Central Office Terminal (COT), has an interface to a digital cross-connect switch (DCS) and communicates with the chain of remote terminals (RT's) through one or two fiber spans. The remote terminals are typically located at geographically diverse locations in order to bring telecommunications service to different service areas.
Terminals can also include Broadband Fiber Banks (BFB's) which connect on one side to the terminal's common control and on another side to a number ot distribution fibers. The distribution fibers connect to fuirther optical network units (ONU's) such as a so-called "brick," a Broadband Remote Transceiver (BRX), or a VEX. These ONU's take fiber on one side and on the other side provide narrowband and broadband services over copper to a number of subscribers.
In order to perform maintenance and provisioning operations on the Litespan.TM. system, a craftsperson may use a Litecraft.TM. product, which is a PC-based product which can be plugged into a COT or RT. Upon connection of a Litecraft.TM. to a system terminal, for (example, via a serial port of the PC and a data link the, Litecraft.TM. product downloads configuration information from the system using a standard telephony communication language, TL-1, and presents the configuration information graphically to the user, beginning with a top-level diagram of the overall system. This top-level diagram shows a configuration of terminals and their operational relationships or connections to each other. When the user clicks on a component of the system, the Litecraft.TM. product retrieves information about that component and presents the retrieved infonnation graphically to the user. This presentation is a number of levels deep, enabling the user first to see the overall system, then to see components in an individual terminal, then to see individual access multiplexers within a terminal, then to see individual cards within an access multiplexer. Moreover the user can open multiple windows and browse through the entire system independently in each such window.
In order to perform its various tasks, a Litecraft.TM. product must download extensive configuration information about the system to which it is connected. Such downloading is usually implemented via TL-1 across a serial communications link. The information is obtained from various terminals in the system.
It is necessary for the Litecraft.TM. craft interface device to parse the incoming TL-1 data blocks which contain the system information. Parsing of any language is!generally accomplished using software state machines, or "finite state automata." In the article "Object Oriented State Machines," Software Development Magazine, September, 1993, Ted Faison discusses generally a way to construct finite state automata using "state objects" to represent various parsing states.